1. Field of the Invention
This invention relates generally to vacuum clamps and more particularly to a vacuum clamp employing a syringe, which is reliable and simple to use.
2. Description of the Related Art
Vacuum syringes with and without an external vacuum source are known in the art. U.S. Pat. No. 4,265,476 issued to Elgart on May 5, 1981 relates to a lighted work-holding device which has a piston and a piston rod inside a cylinder. The piston rod head has resilient O-ring seals. There is no control valve and no toothed jaws. There is no external vacuum source. The clamp is made of metal. The device of Elgart is simply a standard syringe in which the objects are picked up by suction at the aperture. The rest of the invention deals with a latch to keep the clamp as desired.
U.S. Pat. No. 2,947,275 issued to Edmonds on Aug. 2, 1960 relates to a pneumatic clamp with jaws attached to the cylinder body and to the cylinder rod. The jaws are not toothed, and they have no finger holes to aid in opening the jaws. There is external pneumatic power, and the clamp is made of metal.
U.S. Pat. No. 2,517,941 issued to Stubbs on Aug. 8, 1950, U.S. Pat. No. 2,552,304 issued to Arter, Jr. on May 8, 1951, U.S. Pat. No. 2,706,922 issued to Allen on Apr. 26, 1955 also disclose hydraulic clamps and wrenches.
Although metal cylinders with cylinder bodies, cylinder rods having O-ring pistons, with two toothless jaws fastened to the cylinder body and to the cylinder rod, and to control valves for pressure rather than vacuum are available, a need still exists for a vacuum-operated clamp which is reliable and simple to use.
The art described in this section is not intended to constitute an admission that any patent, publication or other information referred to herein is "prior art" with respect to this invention, unless specifically designated as such. In addition, this section should not be construed to mean that a search has been made or that no other pertinent information as defined in 37 C.F.R. .sctn. 1.56(a) exists.